Cryptomatte segments optimization

Optimizing cryptomatte to segments output logic to composite the output iteratively from individual masks instead of loading all masks simultaneously to build the composite from. This significantly reduces the memory footprint.

v2.2.0

• Changes so we can read masks from any crytomatte definition, by its name.

v2.1.0

Hotfix for multiple cryptomatte definitions.
Segments is taken from only the definition named as "cryptomatte". Everything else is ignored for now.

v2.0.0

Supports v2.0.0 of exr2png.

• Added cryptomattes into this repo itself.
• Refactored to add in cryptommate related methods
• Added convenience methods such as to read channels and return numpy arrays

v1.0.1

• Fixed dependencies in setup.py

v1.0.0

First stable release